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31.
Yttrium oxide thin films are deposited by microwave electron cyclotron resonance (ECR) plasma assisted metal organic chemical vapour deposition process using an indegeneously developed Y(thd)3 {(2,2,6,6-tetramethyl-3,5-heptanedionate)yttrium} precursor. Depositions were carried out at two different argon gas flow rates keeping precursor and oxygen gas flow rate constant. The deposited coatings are characterized by X-ray photoelectron spectroscopy (XPS), glancing angle X-ray diffraction (GIXRD) and infrared spectroscopy. Optical properties of the films are studied by spectroscopic ellipsometry. Hardness and elastic modulus of the films are measured by load depth sensing nanoindentation technique. Stability of the film and its adhesion with the substrate is inferred from the nanoscratch test.It is shown here that, the change in the argon gas flow rates changes the ionization of the gas in the microwave ECR plasma and imposes a drastic change in the characteristics like composition, structure as well as mechanical properties of the deposited film. 相似文献
32.
Periodica Mathematica Hungarica - Let D be a division ring with infinite center, K a proper division subring of D and N an almost subnormal subgroup of the multiplicative group $$D^*$$ of D. The... 相似文献
33.
Bhatti BS Strachan JP Breining SR Miller CH Tahiri P Crooks PA Deo N Day CS Caldwell WS 《The Journal of organic chemistry》2008,73(9):3497-3507
In an attempt to generate nicotinic acetylcholine receptor (nAChR) ligands selective for the alpha4beta2 and alpha7 subtype receptors we designed and synthesized constrained versions of anabasine, a naturally occurring nAChR ligand. 2-(Pyridin-3-yl)-1-azabicyclo[2.2.2]octane, 2-(pyridin-3-yl)-1-azabicyclo[3.2.2]nonane, and several of their derivatives have been synthesized in both an enantioselective and a racemic manner utilizing the same basic synthetic approach. For the racemic synthesis, alkylation of N-(diphenylmethylene)-1-(pyridin-3-yl)methanamine with the appropriate bromoalkyltetrahydropyran gave intermediates which were readily elaborated into 2-(pyridin-3-yl)-1-azabicyclo[2.2.2]octane and 2-(pyridin-3-yl)-1-azabicyclo[3.2.2]nonane via a ring opening/aminocyclization sequence. An alternate synthesis of 2-(pyridin-3-yl)-1-azabicyclo[3.2.2]nonane via the alkylation of N-(1-(pyridin-3-ylethylidene)propan-2-amine has also been achieved. The enantioselective syntheses followed the same general scheme, but utilized imines derived from (+)- and (-)-2-hydroxy-3-pinanone. Chiral HPLC shows that the desired compounds were synthesized in >99.5% ee. X-ray crystallography was subsequently used to unambiguously characterize these stereochemically pure nAChR ligands. All compounds synthesized exhibited high affinity for the alpha4beta2 nAChR subtype ( K i < or = 0.5-15 nM), a subset bound with high affinity for the alpha7 receptor subtype ( K i < or = 110 nM), selectivity over the alpha3beta4 (ganglion) receptor subtype was seen within the 2-(pyridin-3-yl)-1-azabicyclo[2.2.2]octane series and for the muscle (alpha1betagammadelta) subtype in the 2-(pyridin-3-yl)-1-azabicyclo[3.2.2]nonane series. 相似文献
34.
Soumya R. Deo Ajaya K. Singh Lata Deshmukh Narendra Pratap Singh Mariya P. Aleksandrova 《Journal of fluorescence》2016,26(2):459-469
The thin films of CdS1-xSex were successfully deposited over glass substrates by chemical bath deposition technique. Cadmium acetate, thiourea and sodium selenosulfate were used as source materials for Cd2+, S2? and Se2? ions, while 2-mercaptoethanol was used as capping agent. The various deposition conditions such as precursor concentration, deposition temperature, pH and deposition time were optimized for the deposition of CdS1-xSex thin films of good quality and the films were annealed at 200° and 300 °C. The structural, morphological, chemical and optical properties were examined by various characterization techniques and discussed in detail. The optical band gap of CdS1-xSex thin film samples were estimated and found in the range from 2.11 to 1.79 eV for as-deposited and annealed thin films. 相似文献
35.
Trends in microRNA detection 总被引:1,自引:0,他引:1
MicroRNAs (miRNAs) are short, ~22 nucleotide length RNAs that perform gene regulation. Recently, miRNA has been shown to be
linked with the onset of cancer and other diseases based on miRNA expression levels. It is important, therefore, to understand
miRNA function as it pertains to disease onset; however, in order to fully understand miRNA’s role in a disease, it is necessary
to detect the expression levels of these small molecules. The most widely used miRNA detection method is Northern blotting,
which is considered as the standard of miRNA detection methods. This method, however, is time-consuming and has low sensitivity.
This has led to an increase in the amount of detection methods available. These detection methods are either solid phase,
occurring on a solid support, or solution phase, occurring in solution. While the solid-phase methods are adaptable to high-throughput
screening and possess higher sensitivity than Northern blotting, they lack the ability for in vivo use and are often time-consuming.
The solution-phase methods are advantageous in that they can be performed in vivo, are very sensitive, and are rapid; however,
they cannot be applied in high-throughput settings. Although there are multiple detection methods available, including microarray
technology, luminescence-based assays, electrochemical assays, etc., there is still much work to be done regarding miRNA detection.
The current gaps of miRNA detection include the ability to perform multiplex, sensitive detection of miRNA with single-nucleotide
specificity along with the standardization of these new methods. Current miRNA detection methods, gaps in these methods, miRNA
therapeutic options, and the future outlook of miRNA detection are presented here. 相似文献
36.
A study is made with an analysis of an incompressible viscous fluid flow past a slightly deformed porous sphere embedded in another porous medium. The Brinkman equations for the flow inside and outside the deformed porous sphere in their stream function formulations are used. Explicit expressions are investigated for both the inside and outside flow fields to the first order in small parameter characterizing the deformation. The flow through the porous oblate spheroid embedded in another porous medium is considered as the particular example of the deformed porous sphere embedded in another porous medium. The drag experienced by porous oblate spheroid in another porous medium is also evaluated. The dependence of drag coefficient and dimensionless shearing stress on the permeability parameter, viscosity ratio and deformation parameter for the porous oblate spheroid is presented graphically and discussed. Previous well-known results are then also deduced from the present analysis. 相似文献
37.
Garg BS Nandan Kumar D 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2003,59(2):229-234
Complexes of nickel(II) of N,N'-disalicylidene-1,2-phenylenediamine (H2dsp), N,N'-disalicylidene-3,4-diaminotoluene (H2dst), 4-nitro-N,N'-disalicylidene-1,2-phenylenediamine (H2ndsp) and N,N'-disalicylidene ethylenediamine (H2salen) have been prepared and characterised by elemental analysis, electronic, IR, magnetic susceptibility measurement, 1H NMR and thermal studies. TG studies show that the Ni(dsp) and Ni(salen) complex decomposed in one step and Ni(dst) and Ni(ndsp) complex in two steps. Kinetic and thermodynamic parameters were computed from the thermal decomposition data. The activation energy of either one step decomposition or two step decomposition of complexes lies 72-95 kJ mol(-1) range. 相似文献
38.
A strategy for the simultaneous detection of multiple microRNA (miRNA) targets was developed utilizing fluorophore/quencher-labeled oligonucleotide probe sets. Two miRNA targets (miR-155 and miR-103), whose misregulation has afforded them status as putative biomarkers in certain types of cancer, were detected using our assay design. In the absence of target, the complementary fluorophore-probe and quencher-probe hybridize, resulting in a fluorescence resonance energy transfer-based quenching of the fluorescence signal. In the presence of unlabeled target, however, the antisense quencher-probe can hybridize with the target, resulting in increased fluorescence intensity as the quencher-probe is sequestered beyond the Förster radius of the fluorescent-probe. The assay design was tested in multiple matrices of buffer, cellular extract, and serum; and detection limits were found to be matrix-dependent, ranging from 0.34 to 8.89 pmol (3.4–59.3 nM) for miR-155 and 2.90–11.8 pmol (19.3–79.0 nM) for miR-103. Single, double, and triple nucleotide selectivity was also tested. Additionally, miR-155 concentrations were assessed in serum samples obtained directly from breast cancer patients without the need for RNA extraction. This assay is quantitative, possesses a low detection limit, can be applied in multiple complex matrices, and can obtain single-nucleotide selectivity. This method can be employed for the multiplex detection of solution-phase DNA or RNA targets and, more specifically, for the direct detection of serum miRNA biomarkers. 相似文献
39.
An organoselenium-based NSe(3) type of tripodal system 2 as a Hg(2+)-selective fluorescence "turn-on" probe is described. The "turn-on" fluorescence behavior of this selenotripod 2 is significant because it depends on Hg-Se bond formation and acts as a reporting unit for this system. The system exhibits immediate response (15 s) with a subnanomolar detection limit (0.1 nM) for the Hg(2+) ion. It efficiently detects both aqueous and nonaqueous Hg(2+) at 2 nM concentration. 相似文献
40.
A simple mechanism of replica symmetry breaking for spin-glass, as suggested by Parisi, has been used to solve the anisotropic
spin-glass model of Sherrington and Ghatak. Temperature variation of the correlation parameters and the resulting variations
with the temperature of the thermodynamic quantities like internal energy, specific heat and entropy have been evaluated.
It is found that the anisotropy has considerable effect on the properties of the spin system. At low temperatures, the specific
heat varies asT
2. However, the entropy is positive for temperatures above 0.1°K, which is a considerable improvement on the results of Sherrington
and Ghatak. The results are expected to be in good agreement with experiment or computer simulation studies near transition
temperatures. 相似文献